Diffractive intraocular lenses for extended range of vision

ABSTRACT

Apparatuses, systems and methods for providing improved ophthalmic lenses, particularly intraocular lenses (IOLs). Exemplary diffractive intraocular implants (IOLs) can include a diffractive profile having multiple diffractive zones. The diffractive zones can include a central zone that includes one or more echelettes and a peripheral zone beyond the central zone having one or more peripheral echelettes. The central diffractive zone can work in a higher diffractive order than a remainder of the diffractive profile. The combination of the central and peripheral zones and an optional intermediate zone provides a longer depth of focus than a diffractive profile defined just by a peripheral and/or optional intermediate zone.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of and claims priority to U.S. patentapplication Ser. No. 15/923911, filed Mar. 16, 2018, which claimspriority to U.S. Provisional Patent Application No. 62/473,200, filedMar. 17, 2017, which is incorporated herein by reference in theirentirety.

BACKGROUND

Embodiments of the present disclosure relate generally to ophthalmiclenses, such as intraocular lenses (IOLs), and particular embodimentsprovide methods, devices, and systems for mitigating or treating visionconditions such as presbyopia via ophthalmic lenses.

SUMMARY

Embodiments herein described include an ophthalmic lens with a firstsurface and a second surface disposed about an optical axis, the lensbeing characterized by a depth of focus across a range of opticalpowers, i.e. an extended depth of focus (EDOF) that achieves an extendedrange of vision (ERV). A diffractive profile is imposed on one of thesurfaces and configured to cause a distribution of non-negligibleamounts of light among the depth of focus. The diffractive profileincludes at least a central zone with at least one central diffractiveechelette having a first phase delay, and a peripheral zone comprisingat least one peripheral diffractive echelette having a second phasedelay less than the first phase delay. In some embodiments, a third,intermediate zone may also be provided comprising at least oneintermediate diffractive echelette having a third phase delay less thanthe first phase delay.

The central zone operates primarily in a higher diffractive order thanthe peripheral zone; and may also operate in a higher diffractive orderthan an optional intermediate zone. The incorporation of the centraldiffractive zone in the lens provides the combined diffractive profile(central zone +peripheral zone) with a longer depth of focus than thatachieved by a diffractive profile defined just by the peripheral zone;and provides a longer depth of focus than a diffractive profile definedby the peripheral and an optional intermediate zone. The peripheral zoneand/or optional intermediate zones may operate primarily in the firstand/or second diffractive orders and distribute light to the far andintermediate ranges of viewing distances; while the central zone, whichoperates primarily in the second or third diffractive orders,distributes light primarily to the intermediate and/or near ranges ofviewing distances. In combination, the combination of the central,peripheral, and optional intermediate diffractive zones provide light toan extended range of viewing distances. Embodiments also provide forhigh total light efficiency, in some cases capturing more than 90% ofincident light in the complete range of vision. Embodiments also corrector partially correct for chromatic aberration in the range of vision.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graphical representation of a first example diffractive lensprofile showing a central diffractive zone having one diffractiveechelette, and a peripheral diffractive zone, according to someembodiments of the present invention;

FIG. 2 is a graphical representation of a second example diffractivelens profile showing a central diffractive zone having multiplediffractive echelettes, and peripheral diffractive zone, according tosome embodiments of the present invention;

FIG. 3 is a graphical representation of simulated visual acuity of anexample diffractive lens according to FIG. 1 compared to a diffractivelens having only a peripheral diffractive profile, according to someembodiments of the present invention;

FIG. 4 is a graphical representation of simulated visual acuity ofexample diffractive lenses having multiple combinations of central andperipheral diffractive zones, according to some embodiments of thepresent invention;

FIG. 5 is a graphical representation showing simulated defocus curves ofexample lenses having varied central diffractive zones, according tosome embodiments of the present invention;

FIG. 6 is a graphical representation of an example diffractive lensprofile, showing a central diffractive zone, peripheral diffractivezone, and intermediate diffractive zone, according to some embodimentsof the present invention;

FIG. 7 is a graphical representation of simulated defocus curves ofexample lenses having a central diffractive zone, intermediatediffractive zone, and peripheral diffractive zone, similar to the lensof FIG. 6 , with comparison to a lens having only peripheral andintermediate diffractive zones, according to some embodiments of thepresent invention;

FIG. 8 is a simplified block diagram illustrating a system forgenerating a diffractive ERV lens surface, in accordance withembodiments;

FIG. 9 illustrates an example process for generating a diffractive ERVlens surface; and

FIG. 10 illustrates an example computing environment for facilitatingthe systems and processes of FIGS. 8 and 9 .

DETAILED DESCRIPTION

In the following description, various embodiments will be described. Forpurposes of explanation, specific configurations and details are setforth in order to provide a thorough understanding of the embodiments.However, it will also be apparent to one skilled in the art that theembodiments may be practiced without the specific details. Furthermore,well-known features may be omitted or simplified in order not to obscurethe embodiment being described.

Embodiments herein disclosed relate to diffractive intraocular lensesfor providing extended depth of focus to a patient (ERV lenses).According to some embodiments, an intraocular lens can include adiffractive profile having a central diffractive zone that works in ahigher diffractive order than a remainder of the diffractive profile.Suitable diffractive lenses can have a light efficiency (i.e., totallight passed to the diffractive orders as a percentage of incidentlight) of approximately 90%, distributed over a defocus range thatcovers at least three different diffractive orders within the visualrange, and with at least a non-zero or non-negligible percentage oflight distributed to each diffractive order. According to someembodiments, a diffractive lens can partially correct for ocularchromatic aberration. In alternative embodiments, the diffractive lenscan fully correct or over-correct for ocular chromatic aberration.

Embodiments of lenses herein disclosed can be configured for placementin the eye of a patient and aligned with the cornea to augment and/orpartially replace the function of the cornea. In some embodiments,corrective optics may be provided by phakic IOLs, which can be used totreat patients while leaving the natural lens in place. Phakic IOLs maybe angle supported, iris supported, or sulcus supported. IOLs can befurther secured with support members that attach the IOL to the eye,e.g., with physical extensions from the IOL into adjacent corneal oriris tissue. Phakic IOLs can also be placed over the natural crystallinelens or piggy-backed over another IOL. Exemplary ophthalmic lensesinclude contact lenses, phakic lenses, pseudophakic lenses, cornealinlays, and the like. It is also envisioned that the lens shapesdisclosed herein may be applied to inlays, onlays, accommodating IOLs,spectacles, and even laser vision correction.

As used herein, non-zero may refer generally to a non-negligible ornon-trivial amount of light, typically at least 10% of the total lightpassing through the lens for IOLs.

Embodiments disclosed herein can provide an extended depth of focus. Insome embodiments, diffractive intraocular lenses herein can providebetter distance, intermediate, and/or near image quality than presentlyavailable multifocal lenses while mitigating certain dysphotopsiaeffects, such as glare or halo.

Methods of manufacture for diffractive lenses as disclosed herein, aswell as methods of treatment utilizing said diffractive lenses, mayinclude techniques described in, e.g., U.S. Pat. No. 9,335,563, entitled“MULTI-RING LENS, SYSTEMS AND METHODS FOR EXTENDED DEPTH OF FOCUS,”which is hereby incorporated by reference.

Diffractive lenses can make use of a material having a given refractiveindex and a surface curvature which provide a refractive power.Diffractive lenses have a diffractive profile which confers the lenswith a diffractive power or power profile that may contribute to thebase power of the lens. The diffractive profile is typicallycharacterized by a number of diffractive zones. When used for ophthalmiclenses these diffractive zones are typically annular lens zones, orechelettes, spaced about the optical axis of the lens. Each echelettemay be defined by an optical zone, a transition zone between the opticalzone and an optical zone of an adjacent echelette, and echelettegeometry. The echelette geometry includes an inner and outer diameterand a shape or slope of the optical zone, a height or step height, and ashape of the transition zone. The surface area or diameter of theechelettes largely determines the diffractive power profile of the lensand the step height of the transition between echelettes largelydetermines the light distribution within the diffractive power profile.Together, these echelettes form a diffractive profile.

ERV intraocular lenses (IOLs) are intended to provide a patient withimproved vision in a range of distances, covering near, intermediate andfar vision. Near range of vision may generally correspond to visionprovided when objects are at distances from about 33 up to 60 cm from asubject eye with the image substantially focused on the subject retina,and may correspond to a vergence of approximately −1.6 D to −3 D.Intermediate range of vision may generally correspond to vision forobjects at a distance between 63 cm up to 1.3 m from a subject eye withthe image substantially focused on the subject retina, and maycorrespond to a vergence of approximately −1.6 D to −0.75 D. Far rangeof vision may generally correspond to vision for objects at any distancegreater than about 1.3 m from a subject eye with the image substantiallyfocused on the subject retina, and may correspond to a vergence of lessthan −0.75 D. In the case of an ERV lens, or a lens having an extendeddepth of focus, the diffractive profile can provide a plurality of focallengths that overlap across a range of optical powers to provide goodvisual acuity throughout the extended depth of focus.

A traditional multifocal diffractive profile on a lens may be used tomitigate presbyopia by providing two or more optical powers, forexample, one for near vision and one for far vision. The diffractivelenses disclosed herein provide an extended depth of focus across arange of optical powers. The concepts disclosed here apply to both ERVlenses and multifocal lenses. The lenses may also take the form of anintraocular lens placed within the capsular bag of the eye, replacingthe original lens, or placed in front of the natural crystalline lens.The lenses may be in the form of a contact lens, most commonly a contactlens that extends the depth of focus, or in any other form mentionedherein.

In some embodiments, a diffractive profile can include multiplediffractive zones, e.g., a central zone that includes one or moreechelettes, and a peripheral zone beyond the central zone having one ormore peripheral echelettes. In some specific embodiments, anintermediate diffractive zone between the central and peripheral zonesmay be added to the diffractive profile. Each diffractive zone mayinclude some form of apodization. In this context, apodization meansthat the light distribution gradually varies between adjacentechelettes, but light remains directed to the same non-negligiblediffractive orders for all echelettes within the zone. In some specificembodiments, a refractive zone may be added to a lens surface outside ofthe peripheral diffractive zone. In some other embodiments one or moreof the diffractive zones comprise apodized diffractive surfaces. Thediffractive properties of each component echelette of a diffractive zoneor diffractive profile are caused by the physical parameters of thecomponent echelettes, e.g. step height, shape, and width. A singleechelette can be characterized by its phase delay, a phase delay of azone can be characterized by the individual phase delays of itscomponent echelettes, and a phase delay of a lens profile can becharacterized by the phase delays of the echelettes and/or zones withinthe profile.

FIG. 1 is a graphical representation of an example lens profile 100having a central echelette 102 that defines a central diffractive zone101 and multiple peripheral echelettes 104 that define a peripheraldiffractive zone 103 of the lens. In some embodiments, a refractive zone114 can extend outside of the peripheral diffractive zone 103. Thecentral diffractive zone 101 extends from a lens center 116 to thecentral zone boundary 105. The peripheral zone 103 extends from thecentral zone boundary 105 to the peripheral zone boundary 106. Thespecific example provides seven peripheral echelettes 104; however,lenses may have more or fewer echelettes in the peripheral zone withoutdeviating significantly from this disclosure. The specific lens profileshown is described below in Table 1. Positions are shown in terms of thediffractive zone boundary relative to the lens center. The position ofeach particular echelette is determined by the position of the firstechelette (e.g. 0.84 mm in the example at Table 1, below,) multiplied bythe squared root of the echelette number.

TABLE 1 Diffractive lens profile 100 (FIG. 1) # of Phase Step HeightPosition Zone Echelettes Delay (λ) (μm) (mm) Central (101) 1 2.51 10.3(107) 0.84 (105) Peripheral (103) 7 1.2  4.9 (108) 2.38 (106) Refractive(114) 0 0 0 >2.38 (114) 

The diffractive lens profile 100 shown in FIG. 1 features a centraldiffractive zone 101 defined by a single central echelette 102 that hasa larger phase delay than the remaining echelettes (approximately 2.51λ). The central zone 101 is joined to the peripheral zone 103 by a stepheight 107 that can be different, and in some cases larger, than thestep heights 108 separating echelettes in the peripheral zone. Phasedelay is defined in terms of the period of the design wavelength, inthis case 550 nm. Phase delay is the difference in phase between thelight having passed through two adjacent echelettes. By virtue of thehigh phase delay, this central echelette operates primarily in the2^(nd) and 3^(nd) diffractive orders, which directs light predominantlytoward the intermediate and near visual ranges. The diffractive profileoutside the central zone, i.e. the peripheral echelettes 104, operatepredominantly in the 1^(st) and 2^(nd) diffractive orders, the 1^(st)diffractive order adding light to the far focal range for distancevision.

The diffractive profile partially corrects chromatic aberration inducedby the ocular media and/or the lens material in the range of visionprovided by the lens. The distributions of light obtained by thecomponents of the example lens 100, and by the total lens, are shownbelow in Table 2. Table 2 refers the light distribution at the farvisual range (i.e. by the first diffractive order) as well as to thelight distribution within the complete visual range provided by thediffractive profile (i.e. distance and extended depth of focus). Thiscomplete visual range is herein defined as the combination of the first,second and third diffractive orders. In alternative embodiments, thevisual range can also include the light distribution for the fourthdiffractive order.

TABLE 2 Light distributions of example lens profile 100 1 Visual Order(Far) Range Peripheral 0.85 0.94 Central + 0.60 0.92 Peripheral

By way of comparison, a bifocal lens typically has a light loss of lessthan 20% of incident light (e.g., in some cases, of about 18% ofincident light). Thus, the example ERV diffractive lens profile 100,which has a light loss of only about 8%, loses less than half as muchlight as a standard multifocal lens. Furthermore, a typical multifocalbifocal profile with a 50:50 light distribution between distance andnear provides with 40% of light for distance vision. The example atTable 2 provides a 20% more light for far, with having a total of 60%light directed to distance.

In alternative embodiments, a lens may have a central diffractive zonedefined by multiple diffractive echelettes rather than a singlediffractive echelette. FIG. 2 , for example, illustrates a diffractivelens profile 200 that is similar to the diffractive lens profile 100,with an expanded central zone 201 having a first central echelette 202and a second central echelette 218 separated by a central step height207. A peripheral zone 203 is characterized by peripheral echelettes 204separated by step heights 208, the peripheral zone ending at aperipheral zone boundary 206. Optionally, a refractive periphery 214 mayextend beyond the peripheral zone boundary 206. In this example profile,the central diffractive zone 201 is connected with the peripheral zone203 by a transition step height 220, which is similar to the transitionstep height 107. According to embodiments, the example lens profile 200can also achieve an extended depth of focus as the diffractive lensprofile 100, and in some cases may further increase light directed tothe 2^(nd) and 3^(rd) diffractive order.

FIG. 3 shows a graphical representation of simulated visual acuities 300of the example lens 100 and a sibling diffractive design in which allechelettes have the same step heights a the peripheral component asshown in Tables 1, above. The calculations of simulated visual acuitywere performed according the methods described in Aixa Alarcon, CarmenCanovas, Robert Rosen, Henk Weeber, Linda Tsai, Kendra Hileman, andPatricia Piers, “Preclinical metrics to predict through-focus visualacuity for pseudophakic patients,” Biomed. Opt. Express 7, 377-1888(2016). The example simulated visual acuities 300 illustrate that theincorporation of the central zone extends the depth of focus withrespect to that provided by the echelettes with steps heights thatdefine the peripheral zone by approximately 1 D (i.e., referring to thedefocus range with a visual acuity over a threshold of about 0.2LogMAR).

In some (general) embodiments, the phase delay in the central echelettecan be larger than 2 λ, and smaller than 4 λ. In specific embodiments,phase delay can range from about 2.3 λ, up to 3.5 λ, or from 2.45 λ, to3.2 λ, or from 2.5 λ, to 2.95 λ. The number of echelettes is determinedbased on the desired geometry of each echelette and the availableradius. The number of echelettes may vary from as few as 8 to up to 32in some specific embodiments within a lens diameter of 6 mm. In specificembodiments, the first echelette may be positioned with an echeletteboundary between 0.5 and 0.9 mm from a center of the lens, with aremainder of the echelettes placed according the position of the firstechelette multiplied by the square root of the echelette number. In someembodiments, the phase delay of the peripheral echelettes can range from1 λ and can be smaller than 2 λ. In specific embodiments, phase delaycan range from about 1 λ up to 1.5 λ, or from 1.2 λ to 1.5 λ, or from1.336 λ to 1.5 λ.

Various peripheral diffractive zone profiles may be combined with anelevated central profile to achieve different specific lensprescriptions. For example, various alternative embodiments ofperipheral diffractive lens profiles are shown below in Table 3.

TABLE 3 Alternative examples of diffractive lens profiles with varyingperipheral zones # of Phase Step Height Position Zone Echelettes Delay(λ) (μm) (mm) Central 1 2.51 10.3 0.84 Peripheral 1 7 1 4.1 2.38Peripheral 3 7 1.366 5.6 2.38

These peripheral zones can be combined with a central zone likedescribed in Table 1. Therefore, the step height of the central zone isconstant across the examples; and the step heights and phase delays ofthe diffractive echelettes in the peripheral zone are modified. In eachexample, the peripheral echelettes have the same step heights across thezone, which vary between 4.1 and 5.6 microns. The position of theechelettes in each peripheral diffractive profile is determined in thesame way for each example combination (i.e. the position of oneparticular echelette is that of the central multiplied by the squareroot of the echelette number).

FIG. 4 shows a graphical representation of simulated visual acuities 400of the example lenses of Table 3, above as compared to these of thesibling diffractive designs in which all echelettes have the same stepheights as the peripheral component 1 and 3 respectively, as shown inTable 3. In all the cases, the combination with the higher order centralechelette provides a longer depth of focus than the peripheral profilealone. The example simulated visual acuities 400 illustrate that, byvarying the phase delays and step heights of the peripheral echelettes,a lens can be tuned to provide greater visual acuity at intermediate ordistance, depending on the desired prescription of the lens.

In some embodiments, the step heights in the central zone can bemodified as well. For example, Table 4, below, illustrates alternativeembodiments having different step heights in the central zone.

TABLE 4 Alternative examples of diffractive lens profiles with varyingcentral zones # of Phase Step Height Position Zone Echelettes Delay (λ)(μm) (mm) Central 1* 1 2.51 10.3 0.84 Central 3 1 3.2 13.13 0.84 *Notethat Central 1 is the same central zone provided above in Tables 1 and3.

The central zone is working between the 2^(nd) and 3^(rd) diffractiveorder for the example Central 1. The central zone is working between the3^(rd) and 4^(th) diffractive order for the example Central 3. The sameperipheral zone 3 as described in the previous example can be combinedwith other central zones. Within the same peripheral zone, allechelettes have the same step height. The light distributions resultingfrom the above-referenced combinations of profiles are shown below inTable 5 for the far visual range (i.e. first diffractive order) as wellas for two different visual ranges. Visual Range 1 contains the lightdistribution for the first, second and third diffractive order, whileVisual Range 2 contains the light distribution for the diffractiveorders at Visual Range 1 as well as the fourth diffractive order:

TABLE 5 Light distributions of diffractive lens profiles with varyingcentral zones 1 Visual Visual Order (Far) Range 1 Range 2 Central 1 +0.44 0.89 0.91 Peripheral Central 3 + 0.43 0.86 0.91 Peripheral

Varying the central zone parameters can adjust the amount of lightdistributed between the intermediate and near range. For combinationsthat have a central zone working between the third and fourthdiffractive order (i.e. combinations with Central 3), there is anadditional, non-trivial amount of light (i.e. greater than 10% ofincoming light) distributed to an additional diffraction order tofurther extend the range of vision . The total light efficiency indistance, intermediate and near is 91%, which is greater than thetypical light efficiencies of multifocal IOLs.

FIG. 5 shows simulated defocus curves 500 showing visual acuity for theexample lenses described above with reference to Tables 4-5. In all thecases, the incorporation of the central zone further enlarges the depthof focus with respect to that provided by the peripheral zone alone.Simulated defocus curves show that the near and intermediate visualperformance for each lens is affected by the change in step height ofthe central zone, i.e., increasing the step height further enlarge thedepth of focus. The combination with the higher step height creates acontinuous range of vision longer than 3 D with at least 0.2 Log MARvisual acuity.

FIG. 6 shows graphical representation of an example lens profile 600having a central echelette 602 in a central diffractive zone 601,multiple intermediate echelettes 606 in an intermediate diffractive zone605, multiple peripheral echelettes 604 in a peripheral diffractive zone603 of the lens, and a refractive zone 614 outside of the peripheraldiffractive zone 603. The central diffractive zone 601 extends from alens center 616 to the central zone boundary 610. The intermediatediffractive zone 605 is added between the central and peripheraldiffractive zones 601, 603, thus extending from the central zoneboundary 610 to the intermediate zone boundary 612. The peripheral zone603 extends from the intermediate zone boundary 612 to the peripheralzone boundary 611. The intermediate diffractive zone 605 may have one ormultiple intermediate echelettes 606. In this example lens profile 600,the intermediate diffractive zone 605 has two echelettes and theperipheral diffractive zone 603 has five. The step heights 609 of theintermediate echelettes 606 are lower than the step heights 608 of theperipheral echelettes 604 in the example shown, however, the stepheights of the intermediate echelettes may be higher than in theperipheral diffractive zone in alternative embodiments. The specificlens profile shown is described below in Table 6. Positions are shown interms of the diffractive zone boundary relative to the lens center. Theposition of each particular echelette is determined by the position ofthe first (i.e. 0.84 mm in the example at Table 6) multiplied by thesquared root of the echelette number.

TABLE 6 Examples of diffractive lens profiles with an intermediate zone# of Phase Step Height Position Zone Echelettes Delay (λ) (μm) (mm)Central (601) 1 2.51 10.3 (607)  0.84 (610) Intermediate (605) 2 1.204.9 (609) 1.46 (612) Peripheral (603) 5 1.366 5.6 (608) 2.38 (611)Refractive (614) 0 0 0 >2.38 (614) 

FIG. 7 shows simulated defocus curves 700 for the example lenses shownin FIG. 6 and described in Table 6 as compared to that of a profilewithout the higher order echelette (i.e. with the same intermediate,peripheral and refractive zones). In that profile, the central echelettehas the same step height as the intermediate zone. FIG. 7 shows that theincorporation of the central echelette increases the depth of focusprovided by the combination of the intermediate and peripheraldiffractive profiles by approximately 1 D, for a cut-off visual acuityof 0.2 LogMAR.

Table 7 shows the light distribution calculated for 3 mm and 5 mm pupilfor the diffractive profile at Table 6 and for a sibling diffractiveprofile that does not incorporate the intermediate zone. Therefore, thissibling profile has also 8 echelettes, being the central the same as inTable 6 and the remaining 7 echelettes according to the description forthe peripheral zone provided in Table 6. Light distribution is shown atTable 7 for distance as well as for the range of vision provided by thelens (i.e. distance and extended depth of focus). Table 7 shows that,for a 3 mm pupil, there is a 58% of light directed to distance when theintermediate zone is included in the diffractive profile, while there isa 44% of light for far without this zone. For a 5 mm pupil the lightdistribution at distance are 61% and 51% for the profiles with andwithout the intermediate zone. Therefore, the incorporation of theintermediate zone 605 (FIG. 6 ) can provide an improvement in the lightdistribution at distance for both photopic (i.e. 3 mm pupil) and mesopicconditions (i.e. 5 mm pupil) as compared to the case when only thecentral and peripheral zones are included in the diffractive profile.Furthermore, the amount of light directed to distance is less affectedby changes in pupil size when the intermediate zone is included in thecombination. While the light directed to distance changes by 5% for thecombination with the intermediate diffractive zone, there is a change of27% in light distribution for distance when only the central andperipheral zones are combined.

TABLE 7 Light distributions of diffractive lens profiles with varyingzone configurations 1 Visual Order (far focus) Range Central + 3 mmpupil 0.58 0.92 Intermediate + 5 mm pupil Peripheral 0.61 0.90 Central1 + 3 mm pupil 0.44 0.89 Peripheral (no 5 mm pupil 0.56 0.89intermediate)

According to various embodiments, the phase delay in the centralechelette can be larger than 2 λ, and smaller than 4λ. In specificembodiments, phase delay can range from about 2.3 λ, up to 3.5 λ, orfrom 2.45 λ, to 3.2 λ, or from 2.5 λ, to 2.95 λ. The number ofechelettes can be determined based on the desired geometry of eachechelette and the available radius. In some specific embodiments, thenumber of echelettes may vary from as few as 8 to up to 32. The firstechelette may be positioned with an echelette boundary between 0.5 and0.9 mm from a center of the lens, with a remainder of the echelettesplaced according the position of the first echelette multiplied by thesquare root of the echelette number. In some embodiments, the phasedelay of the peripheral echelettes can range from 1 λ, and can besmaller than 2 λ. In specific embodiments, phase delay can range fromabout 1 λ, up to 1.5 λ, or from 1.2 λ, to 1.5 λ, or from 1.336 λ, to 1.5X,. In some embodiments, the phase delay of the echelettes in theintermediate zone can be smaller than that of the echelettes at theperipheral zone by 0.05 λ, up to 0.5 λ, or by 0.10 λ, to 0.25 λ. Inalternative embodiments, the phase delay of the echelettes in theintermediate zone may vary. In alternative embodiments, the phase delayof the echelettes in the intermediate zone may be greater than that ofthe echelettes in the peripheral zone by 0.05 λ, up to 0.5 λ, or by 0.05λ, to 0.15 λ.

Exemplary Light Distributions by Diffractive Order

Specific light distributions across the visual range of the extendeddepth of field can be calculated in part on the basis of the portion oflight directed by each diffractive order in each respective diffractivezone. For example, Table 8, below, lists light distributions accordingto diffractive order for a specific embodiment of a diffractive ERV lenssimilar to the lens of FIG. 1 and Table 1, i.e. having central andperipheral diffractive zones, where the central diffractive zoneoperates predominantly in a higher order than the remaining echelettes.As shown, a majority of light that passes through the centraldiffractive zone is directed according to the second and thirddiffractive orders, whereas a majority of light that passes through theperipheral zone is directed according to the first and seconddiffractive orders. Total light distribution for the combined lensprofile is also shown, with approximately 60% of light directed to thefirst diffractive order that provides the distance visual range, and 19%and 14% are directed to the second and third diffractive orders thatcreate the extended depth of focus. All, first, second and thirddiffractive orders have a non-negligible light distribution (i.e.greater than 10%) and create an extended range of vision that coversdistance, intermediate and near as shown in FIG. 3 . The combineddiffractive profile directs 92% of light toward the entire range ofvision. Therefore, it is more efficient than traditional bifocaldiffractive lenses that lose approximately 18% of the light (82% is usedfor the entire range of vision).

TABLE 8 Light Distribution by Diffractive Order across Central andPeripheral Diffractive Zones for profile described in Table 1 1 2 3Visual Order 0 distance EDF EDF 4 Range Central 0.01 0.03 0.43 0.43 0.030.89 Peripheral 0.02 0.85 0.07 0.01 0.00 0.94 Combined 0.02 0.60 0.190.14 0.01 0.92

Table 9, below, lists light distributions according to diffractive orderfor a specific embodiment of a diffractive ERV lens similar to thelenses described in Table 3, i.e. having the same central zone anddifferent peripheral diffractive zones, where the central diffractivezone operates predominantly in a higher order than the remainingechelettes. As shown, a majority of light that passes through thecentral diffractive zone is directed according to the second and thirddiffractive orders. For the peripherall diffractive profile, themajority of light is directed according to the first diffractive order.For the peripheral3 diffractive profile, the majority of light isdirected according to the first and second diffractive orders. Totallight distributions for the combined lens profiles are also shown. Inboth cases, there is a non-negligible amount of light directed to thefirst, second and third diffractive orders. The light distribution fordistance is greater than for the combination with peripheral 1 than forthe combination with peripheral 3. However, the light distribution atthe second diffractive order is greater for the combination with theperipheral 3 profile. That results in a better intermediate performancefor this combination, as shown in FIG. 4 . The light distribution at thethird diffractive order is quite insensitive to modifications in theperipheral diffractive profile. In both cases, the combined diffractiveprofile directs at least 89% of light toward the extended range ofvision. Therefore, it is more efficient than traditional bifocaldiffractive lenses that loss approximately 18% of the light.

TABLE 9 Light Distribution by Diffractive Order across Central andPeripheral Diffractive Zones for profile described in Table 3 1 2 3Visual order 0 distance EDF EDF 4 Range Central 0.01 0.03 0.43 0.43 0.030.89 Peripheral1 0.01 0.98 0.01 0.00 0.00 0.99 Peripheral3 0.04 0.620.23 0.03 0.01 0.89 Central + Peripheral1 0.01 0.68 0.14 0.14 0.01 0.96Central + Peripheral3 0.03 0.44 0.29 0.16 0.02 0.89

Table 10, below, lists light distributions according to diffractiveorder for a specific embodiment of a diffractive ERV lens similar to thelenses described in Table 4, i.e. having the same peripheral anddifferent peripheral central zones, where the central diffractive zonesoperates predominantly in a higher order than the remaining echelettes.As shown for central 1, a majority of light that passes through any ofthe central diffractive zone is directed according to the second andthird diffractive orders. However, for central 3, a majority of lightthat passes through any of the central diffractive zone is directedaccording to the third and fourth diffractive orders. For the peripheraldiffractive profile, the majority of light is directed according to thefirst and second diffractive orders. Total light distributions for thecombined lens profiles are also shown. For the combination with central1, there is a non-negligible amount of light directed to the first,second and third diffractive orders. For the combination with central 3,there is a non-negligible amount of light directed to the first, second,third and fourth diffractive orders. That results in longer depth offocus for this combination, as shown in FIG. 5 . In both cases, thecombined diffractive profile directs at least 89% of light toward theextended range of vision. Therefore, it is more efficient thantraditional bifocal diffractive lenses that loss approximately 18% ofthe light.

TABLE 10 Light Distribution by Diffractive Order across Central andPeripheral Diffractive Zones for profile described in Table 4 1 2 3 4Visual order 0 distance EDF EDF EDF Range Central 1 0.01 0.03 0.43 0.430.03 0.89 Central 3 0.00 0.01 0.03 0.76 0.15 0.95 Peripheral 0.04 0.620.23 0.03 0.01 0.89 Central1 + Peripheral 0.03 0.44 0.29 0.16 0.02 0.89Central3 + Peripheral 0.03 0.43 0.17 0.26 0.06 0.91

Table 11, below, lists light distributions according to diffractiveorder for a specific embodiment of a diffractive ERV lens similar to thelens of FIG. 7 and Table 6, i.e. having central, intermediate, andperipheral diffractive zones, where the central diffractive zoneoperates predominantly in a higher order than the remaining zones. Asshown, a majority of light that passes through the central diffractivezone is directed according to the second and third diffractive orders,whereas a majority of light that passes through the intermediate andperipheral zones is directed according to the first and seconddiffractive orders. Total light distribution for the combined lensprofile is also shown, with approximately 58% of light directed to thefirst diffractive order, which provides the distance visual range, and19% and 15% are directed to the second and third diffractive orders,which create the extended depth of focus. All, first, second and thirddiffractive orders have a non-negligible light distribution (i.e.greater than 10%) and create an extended range of vision that coversdistance, intermediate and near as shown in FIG. 7 . The combineddiffractive profile directs 92% of light toward the extended range ofvision. Therefore, it is more efficient than traditional bifocaldiffractive lenses that loss approximately 18% of the light.

TABLE 11 Light Distribution by Diffractive Order across Central,Intermediate, and Peripheral Diffractive Zones for profile described inTable 6 1 2 3 Visual Order 0 distance EDF EDF 4 range Central 0.01 0.030.43 0.43 0.03 0.89 Intermediate 0.02 0.85 0.07 0.01 0.00 0.94Peripheral 0.04 0.62 0.23 0.03 0.01 0.89 Combined 0.02 0.58 0.19 0.150.01 0.92

According to various embodiments, between 43% and 68% of light may bedirected to the 1^(st) diffractive order, which provides the distancevisual range, between 14% and 29% may be directed to the seconddiffractive order and between 14% and 26% may be directed to the thirddiffractive order, which creates the extended depth of focus. It isfurther envisioned that for creating useful vision in the intermediateand/or near distances, a non-negligible amount of light of at least 10%should be directed to the second and third diffractive order.Considering the total light loss being at least 4%, the maximum amountof light in the 1st order in this case would be 75%. In order to createmaximum visual quality in the intermediate and/or near range withoutdetrimental effect on distance vision, a maximum amount of light of 30%may be directed to the second and/or third diffractive order. As aresult, the minimum amount for the first diffractive order would be 40%.Thus, the range for the first diffractive order may be between 40% and75%, and the ranges for the second and third diffractive orders may bebetween 10% and 30%.

Systems and Methods for Determining the Diffractive Power Profile:

FIG. 8 is a simplified block diagram illustrating a system 800 forgenerating a diffractive profile having at least a central higher orderechelette and a peripheral zone, in accordance with embodiments. Thesystem 800 may, in some cases, be used to include an intermediate zone.The system 800 may also be used to produce IOLs conforming to theembodiments.

The system 800 includes a user input module 802 configured to receiveuser input defining aspects of an intraocular lens. Inputs to design anintraocular lens may include a patient's visual needs, cornealaberrations (or corneal topography, from which corneal aberrations canbe retrieved), a pupil size performance, and lens dimensions, amongother attributes. A simulated optical or visual performance can becalculated from patient's visual needs that represent the desired visualperformance of the patient after the surgery. In some cases, a desiredoptical performance may relate to a patient's lifestyle, e.g., whetherthe patient prefers to participate in activities requiring predominantlydistance vision, intermediate vision, or near vision without additionalvisual correction. The power profile prescription can be calculated fromthe simulated performance including, for example, a preferred opticalpower or optical power profile for correcting far vision and expecteddepth of focus. The corneal aberrations (or corneal wave frontaberrations) can include the higher order rotationally symmetricalaberrations of the cornea as a function of the pupil size. A pupil sizeperformance can include a pupil diameter of a patient under differentlighting conditions. These parameters can also be related to patient'slife style or profession, so that the design incorporates patient'svisual needs as a function of the pupil size. In some cases, parameterssuch as lens asphericity can be determined based on a function of thewave front aberrations and visual needs of the patient. Lens dimensionscan include a preferred radius of the total lens, and may furtherinclude preferred thickness, or a preferred curvature of one or theother of the anterior surface and posterior surface of the lens, as wellas the optional incorporation of toricity in any of the IOL surfaces.

A diffractive profile modeling module 804 can receive information aboutthe desired lens from the user input module 802, and can determineaspects of the diffractive profile. For example, the diffractive profilemodeling module 804 can determine the position and heights of theechelette of the central zone. It can also determine the position,number and height of the echelettes in peripheral zones required tofulfill the performance determined from patient's visual needs. Themodule can determine the need of including an intermediate zone, as wellas the structural characteristics of the zone (number and heights of theechelettes). The base curvature of the profile can be related to thebiometry of the patient. The asphericity can also be related to that ofthe patient's cornea, so that it either compensates patient's cornealspherical aberration or induces a certain amount of spherical aberrationto help improving intermediate and near performance in mesopicconditions.

The diffractive profile modeling module 804 can be configured togenerate performance criteria 812, e.g. via modeling optical propertiesin a virtual environment. Performance criteria can include the match ofthe expected performance derived from patient's visual needs to that ofthe actual diffractive profile that results from 804. In some cases, thediffractive profile modeling module 804 can provide an intraocular lenssurface to an intraocular lens fabrication module 808 for facilitatingthe production of a physical lens, which can be tested via anintraocular lens testing module 810 for empirically determining theperformance criteria 812, so as to identify optical aberrations andimperfections not readily discerned via virtual modeling, and to permititeration.

FIG. 9 is an example process 900 for generating a refractive ERV lenssurface, in accordance with embodiments. The process 900 may beimplemented in conjunction with, for example, the system 800 shown inFIG. 8 . Some or all of the process 900 (or any other processesdescribed herein, or variations, and/or combinations thereof) may beperformed under the control of one or more computer systems configuredwith executable instructions and may be implemented as code (e.g.,executable instructions, one or more computer programs, or one or moreapplications) executing collectively on one or more processors, byhardware or combinations thereof. The code may be stored on acomputer-readable storage medium, for example, in the form of a computerprogram comprising a plurality of instructions executable by one or moreprocessors. The computer-readable storage medium may be non-transitory.

The process 900 includes receiving an input indicative of a patient'svisual needs (act 902). The input can include, e.g., a desired opticalpower profile for correcting impaired distance vision, a desired opticalpower profile for correcting impaired intermediate vision, a desiredoptical power profile for accommodating near vision, and any suitablecombination of the above. Next, a diffractive ERV lens profile can bedefined according to the visual needs determined above (act 904). Insome cases, the diffractive profile may be defined for providing anextended depth of focus by, e.g., defining a central diffractive zoneincluding one more echelettes configured to operate primarily in thesecond and/or third and/or fourth diffractive orders, where the centraldiffractive zone is operable to direct incident light to a range ofdistances to further enlarge the depth of focus of the diffractiveprofile. The diffractive profile may be further defined to include aperipheral diffractive zone configured to operate primarily in a firstand/or second diffractive order, or a lower diffractive order than thecentral diffractive zone, that is operable to direct light to a range ofdistances corresponding to the intermediate and/or far visual range. Adiffractive lens surface can then be generated based on the diffractiveprofile (act 906). The system can then generate instructions tofabricate an intraocular lens based on the generated diffractive lenssurface (act 908).

FIG. 10 is a simplified block diagram of an exemplary computingenvironment 1000 that may be used by systems for generating thecontinuous progressive lens surfaces of the present disclosure. Computersystem 1000 typically includes at least one processor 1052 which maycommunicate with a number of peripheral devices via a bus subsystem1054. These peripheral devices may include a storage subsystem 1056comprising a memory subsystem 1058 and a file storage subsystem 1060,user interface input devices 1062, user interface output devices 1064,and a network interface subsystem 1066. Network interface subsystem 1066provides an interface to outside networks 1068 and/or other devices,such as the lens fabrication module 808 or lens testing module 810 ofFIG. 8 . In some cases, some portion of the above-referenced subsystemsmay be available in a diagnostics device capable of measuring thebiometric inputs required for calculating attributes such as base power.

User interface input devices 1062 may include a keyboard, pointingdevices such as a mouse, trackball, touch pad, or graphics tablet, ascanner, foot pedals, a joystick, a touchscreen incorporated into thedisplay, audio input devices such as voice recognition systems,microphones, and other types of input devices. The input devices 1062may also include one or more biometric input devices capable ofmeasuring a patient's biometric inputs required to generate thediffractive lens surface. For example, input devices 1062 can include abiometer capable of measuring axial length, corneal power, cornealaberrations, preoperative anterior chamber depth, lens thickness, and/orpupil size for a patient under different lighting conditions. Thesevariables are nonlimiting and are mentioned herein by way of example.User input devices 1062 will often be used to download a computerexecutable code from a tangible storage media embodying any of themethods of the present invention. In general, use of the term “inputdevice” is intended to include a variety of conventional and proprietarydevices and ways to input information into computer system 1022.

User interface output devices 1064 may include a display subsystem, aprinter, a fax machine, or non-visual displays such as audio outputdevices. The display subsystem may be a cathode ray tube (CRT), aflat-panel device such as a liquid crystal display (LCD), a projectiondevice, or the like. The display subsystem may also provide a non-visualdisplay such as via audio output devices. In general, use of the term“output device” is intended to include a variety of conventional andproprietary devices and ways to output information from computer system1022 to a user.

Storage subsystem 1056 can store the basic programming and dataconstructs that provide the functionality of the various embodiments ofthe present invention. For example, a database and modules implementingthe functionality of the methods of the present invention, as describedherein, may be stored in storage subsystem 1056. These software modulesare generally executed by processor 1052. In a distributed environment,the software modules may be stored on a plurality of computer systemsand executed by processors of the plurality of computer systems. Storagesubsystem 1056 typically comprises memory subsystem 1058 and filestorage subsystem 1060. Memory subsystem 1058 typically includes anumber of memories including a main random access memory (RAM) 1070 forstorage of instructions and data during program execution.

Various computational methods discussed above, e.g. with respect togenerating a diffractive lens surface, may be performed in conjunctionwith or using a computer or other processor having hardware, software,and/or firmware. The various method steps may be performed by modules,and the modules may comprise any of a wide variety of digital and/oranalog data processing hardware and/or software arranged to perform themethod steps described herein. The modules optionally comprising dataprocessing hardware adapted to perform one or more of these steps byhaving appropriate machine programming code associated therewith, themodules for two or more steps (or portions of two or more steps) beingintegrated into a single processor board or separated into differentprocessor boards in any of a wide variety of integrated and/ordistributed processing architectures. These methods and systems willoften employ a tangible media embodying machine-readable code withinstructions for performing the method steps described above. Suitabletangible media may comprise a memory (including a volatile memory and/ora non-volatile memory), a storage media (such as a magnetic recording ona floppy disk, a hard disk, a tape, or the like; on an optical memorysuch as a CD, a CD-R/W, a CD-ROM, a DVD, or the like; or any otherdigital or analog storage media), or the like.

The particulars shown herein are by way of example and for purposes ofillustrative discussion of the preferred embodiments of the presentinvention only and are presented in the cause of providing what isbelieved to be the most useful and readily understood description of theprinciples and conceptual aspects of various embodiments of theinvention. In this regard, no attempt is made to show structural detailsof the invention in more detail than is necessary for the fundamentalunderstanding of the invention, the description taken with the drawingsand/or examples making apparent to those skilled in the art how theseveral forms of the invention may be embodied in practice.

The following definitions and explanations are meant and intended to becontrolling in any future construction unless clearly and unambiguouslymodified in the following examples or when application of the meaningrenders any construction meaningless or essentially meaningless. Incases where the construction of the term would render it meaningless oressentially meaningless, the definition should be taken from Webster'sDictionary, 3^(rd) Edition or a dictionary known to those of skill inthe art, such as the Oxford Dictionary of Biochemistry and MolecularBiology (Ed. Anthony Smith, Oxford University Press, Oxford, 2004).

As used herein and unless otherwise indicated, the terms “a” and “an”are taken to mean “one”, “at least one” or “one or more”. Unlessotherwise required by context, singular terms used herein shall includepluralities and plural terms shall include the singular.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words ‘comprise’, ‘comprising’, and thelike are to be construed in an inclusive sense as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to”. Words using the singular or pluralnumber also include the plural and singular number, respectively.Additionally, the words “herein,” “above,” and “below” and words ofsimilar import, when used in this application, shall refer to thisapplication as a whole and not to any particular portions of theapplication.

The description of embodiments of the disclosure is not intended to beexhaustive or to limit the disclosure to the precise form disclosed.While the specific embodiments of, and examples for, the disclosure aredescribed herein for illustrative purposes, various equivalentmodifications are possible within the scope of the disclosure, as thoseskilled in the relevant art will recognize.

All references, including patent filings (including patents, patentapplications, and patent publications), scientific journals, books,treatises, technical references, and other publications and materialsdiscussed in this application, are incorporated herein by reference intheir entirety for all purposes.

Aspects of the disclosure can be modified, if necessary, to employ thesystems, functions, and concepts of the above references and applicationto provide yet further embodiments of the disclosure. These and otherchanges can be made to the disclosure in light of the detaileddescription.

Specific elements of any foregoing embodiments can be combined orsubstituted for elements in other embodiments. Furthermore, whileadvantages associated with certain embodiments of the disclosure havebeen described in the context of these embodiments, other embodimentsmay also exhibit such advantages, and not all embodiments neednecessarily exhibit such advantages to fall within the scope of thedisclosure.

While the above provides a full and complete disclosure of exemplaryembodiments of the present invention, various modifications, alternateconstructions and equivalents may be employed as desired. Consequently,although the embodiments have been described in some detail, by way ofexample and for clarity of understanding, a variety of modifications,changes, and adaptations will be obvious to those of skill in the art.Accordingly, the above description and illustrations should not beconstrued as limiting the invention, which can be defined by theappended claims.

1. An ophthalmic lens, comprising: a first surface and a second surfacedisposed about an optical axis, the lens being characterized by anextended depth of focus across a range of optical powers; and adiffractive profile imposed on one of the first and second surfaces andconfigured to cause a distribution of non-negligible amounts of light tothe extended depth of focus, the diffractive profile comprising: acentral zone comprising at least one central diffractive echelettehaving a first phase delay; and a peripheral zone comprising one or moreperipheral diffractive echelettes having a second phase delay less thanthe first phase delay; wherein the central zone operates primarily in ahigher diffractive order than the peripheral zone; and the combinationof the central and peripheral zones provides a longer depth of focusthan a diffractive profile defined just by the peripheral zone.
 2. Theophthalmic lens of claim 1, wherein the peripheral zone operatesprimarily in the first diffractive order.
 3. The ophthalmic lens ofclaim 1, wherein the peripheral zone operates primarily in the first andsecond diffractive orders.
 4. The ophthalmic lens of claim 1, whereinthe central zone operates primarily in the second and third diffractiveorders.
 5. The ophthalmic lens of claim 1, wherein the central zoneoperates primarily in the third and fourth diffractive orders. 6-12.(canceled)
 13. The lens of claim 1, wherein the at least one centraldiffractive echelette in the central zone has a phase delay of more than2.0 λ, and wherein the one or more peripheral diffractive echeletteshave phase delay of less than 2.0 λ.
 14. (canceled)
 15. The lens ofclaim 1, wherein the central optical zone has a phase shift from 2 λ, to4 λ, and wherein the peripheral optical zone has a phase shift from 1 λ,to 2λ.
 16. The lens of claim 1, wherein the central optical zonecomprises 1 to 2 central echelettes, and wherein the peripheral opticalzone comprises 6 to 7 peripheral echelettes.
 17. The ophthalmic lens ofclaim 1, further comprising: an intermediate zone comprising at leastone intermediate echelette having a phase delay that is different thanthe phase delay of the peripheral and central zones.
 18. The ophthalmiclens of claim 17, wherein the intermediate zone operates primarily inthe first and second diffractive orders.
 19. (canceled)
 20. Theophthalmic lens of claim 17, wherein the phase delay of the at least oneechelette in the intermediate zone is smaller than that of the one ormore peripheral diffractive echelettes by 0.10 λ, up to 0.15 λ. 21.(canceled)
 22. The ophthalmic lens of claim 17, wherein the phase delayof the at least one echelette in the intermediate zone is greater thanthat of the one or more peripheral diffractive echelettes by 0.05 λ, upto 0.15 λ.
 23. The ophthalmic lens of claim 17, wherein there is anon-negligible light distribution in the first, second and thirddiffractive orders of the diffractive profile.
 24. The ophthalmic lensof claim 1, wherein there is a non-negligible light distribution in thefirst, second, third and fourth diffractive orders of the diffractiveprofile. 25-37. (canceled)
 38. An ophthalmic lens, comprising: a firstsurface and a second surface disposed about an optical axis, the lensbeing characterized by an extended depth of focus across a range ofoptical powers; and a diffractive profile imposed on one of the firstand second surfaces and configured to cause a distribution ofnon-negligible amounts of light to the extended depth of focus providedby the lens wherein the diffractive profile comprises a centraldiffractive zone that works in a higher diffractive order than aremainder of the diffractive profile. 39-40. (canceled)
 41. The lens ofclaim 38, wherein the central diffractive zone has a phase delay from2.3 λ to 3.5 λ.
 42. The lens of claim 38, wherein the centraldiffractive zone has a phase delay from 2.45 λ to 3.2 λ.
 43. The lens ofclaim 38, wherein the central diffractive zone has a phase delay from2.5 λ to 2.95 λ. 44-52. (canceled)
 53. The lens of claim 38, wherein:the central diffractive zone has a phase delay equal to or larger than2λ; and the remainder of the diffractive profile comprises echelettesthat operate in the first order diffraction regime and have phase delaysless than 2λ.
 54. (canceled)